This invention relates to hydroponic units and more particularly to a window-box size unit having an automatic irrigation system.
The use of plant boxes in hydroponic gardening has long been known. See, for example, U.S. Pat. No. 2,189,510, disclosing a box or tank for growing flowers, vegetables and other plants. See also U.S. Pat. No. 3,667,157; U.S. Pat. No. RE 21,820; and U.S. Pat. No. 3,134,195. Such hydroponic units have not been widely used, primarily because of problems as to providing the plants with sufficient nutrient solution to obtain adequate growth. More recently, hydroponic units using automatic irrigation systems have been developed. In these units, an electric pump is used to pump an air-nutrient solution mixture into a box or tray holding the growing medium and plants. A variety of tubes, pumps, and clamps are currently being used in such systems, for the pumping of the air-nutrient solution mixture into the growing medium for absorption and use by the plants placed therein. In one such unit, irrigation tubes in the form of a "T" with extensions from the arms of the "T" are positioned in the growing medium and connected to a pump, whereas in another unit an airline runs directly from a pump to a nutrient solution tube, to cause the air-nutrient solution mixture to pass through the bottom of the growing medium.
Although such automatic irrigation systems have solved many of the problems of hydroponic gardening, difficulties have remained. Some units, for example, have required cycles of plugging in and unplugging of the pump to avoid over-supply of nutrient solution, while others have proven to be too bulky and difficult to handle or unduly costly for the typical user. Most importantly, presently available hydroponic units have failed to provide a continuous and yet trouble-free means for supplying the growing medium with an adequate supply of the air-nutrient mixture.